Research Credits determine the amount of data you can get from Ranking Research, Keyword Research and Link reports.
Research credits are refreshed on the first day of the month. Unused credits at the end of the month do not roll over to the following month.
Most of these reports consume credits per row returned. A "row" typically refers to one row in a data table on the page. Some reports have multiple tables on them, and the number of credits used will be the sum of all rows in all tables on the report.
Ranking Research: 1 credit / row
Keyword Research (related keywords): 150 credits / query (returns up to 1,000 results)
Keyword Research (search volume lookups): 1 credit / row (minimum 150 credits)
All link tools: 5 credits / row
For example, viewing or exporting the top 300 keywords in Ranking Research would consume 300 research credits.